'\" t
.\"     Title: CHECKPOINT
.\"    Author: The PostgreSQL Global Development Group
.\" Generator: DocBook XSL Stylesheets v1.75.2 <http://docbook.sf.net/>
.\"      Date: 2011-12-01
.\"    Manual: PostgreSQL 9.1.2 Documentation
.\"    Source: PostgreSQL 9.1.2
.\"  Language: English
.\"
.TH "CHECKPOINT" "7" "2011-12-01" "PostgreSQL 9.1.2" "PostgreSQL 9.1.2 Documentation"
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.SH "NAME"
CHECKPOINT \- force a transaction log checkpoint
.\" CHECKPOINT
.SH "SYNOPSIS"
.sp
.nf
CHECKPOINT
.fi
.SH "DESCRIPTION"
.PP
Write\-Ahead Logging (WAL) puts a checkpoint in the transaction log every so often\&. (To adjust the automatic checkpoint interval, see the run\-time configuration options
checkpoint_segments
and
checkpoint_timeout\&.) The
CHECKPOINT
command forces an immediate checkpoint when the command is issued, without waiting for a scheduled checkpoint\&.
.PP
A checkpoint is a point in the transaction log sequence at which all data files have been updated to reflect the information in the log\&. All data files will be flushed to disk\&. Refer to
Chapter 29, Reliability and the Write-Ahead Log, in the documentation
for more information about the WAL system\&.
.PP
If executed during recovery, the
CHECKPOINT
command will force a restartpoint rather than writing a new checkpoint\&.
.PP
Only superusers can call
CHECKPOINT\&. The command is not intended for use during normal operation\&.
.SH "COMPATIBILITY"
.PP
The
CHECKPOINT
command is a
PostgreSQL
language extension\&.
